Mine water desanding apparatus



Jan. 1, 1963 c. o. RAINS MINE WATER DESANDING APPARATUS Filed Nov. 15, 1959 INVENTOK. c. 0. EA N s BYWM/ 7 A TTORNEYS 3,i 71,249 MINE WATER B'ESANDHNG APEARATUS Cloral (It. Rains, Bartlesviiie, Olden, assignor to Phillips Petroleum tCompany, a corporation or iilelaware Filed Nov. 13, 195%, Ser. No. 852,794 2 Claims. (iii. 210-128) This invention relates to an apparatus for desanding and removing abrasive solids from mine water to prepare same for removal from the mine by pumping.

The uranium mines in the Ambrosia Lake area of New Mexico produce considerable quantities of water in the formation being mined. Part of this water actually flows into the mine shafts, while an additional part is connate water found in the pores of the roclt being mined which is freed when the rock is disintegrated. The rock is not especially well cemented and, this fact together with large amounts of water present, results in the formation of a slush or slurry formed of relatively small pieces of rock when the ore is broken up during the mining operation.

Trucks and other mine equipment moving thru the main tunnels work up the floor of the tunnel into a veritable mush. The tunnels are built on a slope and trenches are provided along the wall of each tunnel so that water, mush, slush, etc, drain down these trenches to a sump from which a desanding unit can be operated. This slurry, containing wood chips from mine timbers and other debris, is passed over a screen to remove such pieces before passing into the sump. The Water from the sump is pumped out of the mine thru the mine shaft and because of the coarse abrasive sand and other rock particles in the slurry or suspension the pumps are rapidly abraded and require frequent repair and replacement. This in vention is concerned with an effective method and apparatus for removing most of the abrasive material from the slurry, leaving therein principally 150 mesh particles of relatively soft clay which have little abrasive action on the pumps.

Accordingly, it is an object of the invention to provide an apparatus for removing abrasive solids from mine water preparatory to pumping the water out of the mine. Another object is to reduce the solids content of mine water before pumping the same to ground level. A further object is to provide an apparatus which reduces abrasion on pumping equipment used in removing water from a mine. It is also an object of the invention to provide appartus for removing substantially all of the abrasive solids of +150 mesh from mine Water and recovering mineral values therefrom, which apparatus is compact and relatively inexpensive. Other objects will become apparent upon consideration of the accompanying disclosure.

The invention comprises a liquid-solids cyclone separator; a pump adjacent the sump having its inlet extending to a lower level of the sump and its outlet connected by conduit with the feed inlet of the cyclone separator; a screw type inclined classifier positioned with its lower end below the outlet of the cyclone separator and with its upper end over a slusher trench separate from the sump for delivering solids thereto; means for conveying the heavy solids-liquid material from the cyclone separator to the lower end of the classifier; means for conveying overflow liquid from the lower end of the classifier to the sump; and a disposal line connected with the lighter solids-liquid outlet of the cyclone separator. The apparatus also includes a return conduit from the lighter solidsliquid outlet of the cyclone to the sump with a first floatcontrolled valve therein having a float at a selected level in the sump adapted to close the said first valve as the float rises; and a second float-controlled valve in the disposal line having a float at a selected level in the sump Fatented Jan. 1, 1953.

adapted to close said second valve as the second float lowers. This arrangement of apparatus maintains a liquid level within a narrow range in the sump so that the pump is always provided with an aqueous stream. Continuously operating stirrers are provided in the sump.

A more complete understanding of the invention may be had from a consideration of the accompanying schematic pictorial drawing.

Referring to the drawing, a slusher trench 10 is dug into the floor 11 of a mine tunnel 12 and is provided .with steel rails 14 on the sides and bottom. A partition 16 is provided at one end of the trench. An excavation at the end of the trench provides a compartment 18 and a sump 2%) which are separated by a concrete wall 22. The bottom of the trench, as well as the bottom of the compartment and sump are provided with a layer of concrete 24 and the walls 26 are also lined with concrete.

A drainage ditch 28 in the floor of the mine tunnel empties into sump 2i} and is provided with screen 30 to catch wood shavings and other debris in the aqueous slurry passing into the sump. A centrifugal pump 32 is positioned with its intake in sump 20 below the operating level of water therein and is connected by a conduit 34 with the feed inlet of cyclone separator 36. The coarse-solids liquid discharge outlet 35 of cyclone 36 delivers the discharge eiiluent into box 38 which feeds into an inclined chute 4% leading to inclined screw type classiher 42, provided with screw &3 which is operated by motor 44. Classifier 42 is supported by upright posts (not shown) and by the upper edge of wall or partition 16 in a position to deliver solids from the upper end of the classifier to slusher trench 1-0. A return trough leads from the lower overflow end of the classifier to sump 20. The discharge outlet of cyclone 36 for the aqueous-lighter solids stream is connected with delivery line 52 which forms a T with return line 54, leading to the sump, and with line 55 leading to pump 58 for discharge from the mine thru conduit 60.

In order to control the level of liquid in sump 20, a first float-operated valve 62 is positioned in return line 54 and provided with float 64. Float 64 operates to close valve 62 as the float rises. A second float-operated valve '66 is provided with float 68 which operates to close valve 66 as the float lowers in the sump. In this manner, as the level of liquid in sump 20 lowers, valve 66 is progressively closed and valve 62 is progressively opened so as to return more liquid to the sump. As the level rises, the opposite action of these valves returns less liquid to the sump and delivers more to the exhaust line 56. Electrically operated stirrers 70 are provided in sump 20 to maintain solids in suspension for delivery to the cyclone thru pump 32.

In operation, a slush comprising water and a suspension or slurry of solidsranging from fine to coarse, such as from 460 or 500 mesh to aggregates of 4 or 5 mesh, flows from drainage ditch 28 over screen 31 into sump 2d. The suspension of solids is maintained in the sump by stirrers 70. Pump 32, which is typically a Flygt pump, pumps the slurry or suspension of solids into the feed inlet of cyclone 36 thru line 34. The aqueous feed is separated by centrifugal force in conventional manner in cyclone 36 into a heavier solids stream which is discharged into box 38 and passes to classifier d2 thru trough or chute 40, and a lighter solids stream which is discharged thru line 52 to be passed to pump 58 thru line 56 and/or thru return line 54 to sump 20, depending upon the level of liquid in the sump.

It has been found that the cyclone separator separates substantially all of the solids of mesh size from the feed and delivers the same to the classifier while most of the l50 mesh size particles, comprising principally less abrasive clay, are passed with the overhead stream discharged thru line 52. The effectiveness of the separation step in removing +150 mesh particles is controlled by the pump 32 and cyclone 36 in known manner.

The coarser solids and water passed thru classifier 42 are separated by screw 43 which augers the coarse solids to the upper end of the classifier while allowing the water and fine solids to drain therefrom and to overflow the lower end of the classifier into trough 50.

In this manner, the solids with only the adhering Water are fed over the upper end of the classifier into the slusher trench from which they are removed by an electrically operated oscillating scraper (not shown) which is moved back and forth in the trench so as to pull solids into a loader (not shown) from which they are removed from the mine shaft by conventional equipment to be processed for uranium or other values contained therein.

As before described, floats 64 and 68 maintain a liquid level in sump between a desired minimum and a maximum level by automatically operating valves 62 and 66 to control the amount of return liquid and the amount discharged to the evacuating pump 58.

The apparatus substantially as disclosed and shown in the drawning, utilizing a Krebbs Model D 20 LB cyclone, a Denver Equipment Co., screw classifier, and a Flygt pump has been operating efliciently for a substantial period in a uranium mine in the Grants, New Mexico, area. Typical operating conditions are set forth below.

Cyclone Feed1000 g.p.m. 5% solids Underflow-100 g.p.m. 9% solids Overflow900 g.p.m. 4% solids 150 mesh separation of feed at the following sieve analyses:

Wt. percent on screen: U.S. screen No.

.006 1a .004 20 1.080 40 9.420 60 Sand 7.660 100 530 150 1.120 200 80140 On ani Screw Classifier Before installation of the cyclone-classifier combination, a classifier only was utilized for solids-water separation. The pump utilized in removing water from the mine (pump 58) was a Gould centrifugal pump costing approximately $2000-. Over a long period of operation, this pump required a new impeller and wear rings every 2 weeks and a new pump every 2 months because of wear thru of the case. The upkeep cost about $1500 per month. Since installation of the invention, the cost of upkeep on the Gould pump has been greatly reduced and the best estmate that can be made, at this time with limited operating experience, is that the cost of pump upkeep will be about 10% of the former cost.

Certain modifications of the invention will become apparent to those skilled in the art and the illustrative details disclosed are not to be construed as imposing unnecessary limitations on the invention.

I claim:

1. Apparatus for separating solids from water in a mine comprising in combination, a slusher trench below the mine floor; a sump below the mine floor; a drainage ditch in the mine floor draining into said sump; a liquidsolids cyclone separator having a feed inlet in an upper section, a heavier solids-liquid outlet in its bottom, and a lighter solids-liquid outlet in its top; a return conduit from said lighter solids-liquid outlet to said sump; a first floatcontrolled valve in said return conduit having a float at a selected level in said sump adapted to close said first valve as said float rises; a pump having its inlet in a lower level of said sump and its outlet connected by conduit with the feed inlet of said cyclone separator; a screw type inclined classifier positioned with its lower end below the outlet of said cyclone separator and with its upper end over said slusher trench for delivery of solids thereto; a disposal line connected with said lighter solids-liquid outlet; a second float-controlled valve in said disposal line having a second float at a selected level in said sump adapted to close said second valve as said second float lowers, said first and second float-controlled valves being arranged such that one of said valves is at least partially open at all times during operation of said pump; means for conveying the heavier solids-liquid material from said cyclone separator to the lower end of said classifier; means for conveying overflow liquid from the lower end of said classifier to said sump; and means for operating the screw of said classifier.

2. The apparatus of claim 1 including stirring means in said sump for maintaining a suspension of solids there- 11H.

References Cited in the file of this patent UNITED STATES PATENTS 2,081,398 Giles May 25, 1937 2,225,973 Brown et al Dec. 24, 1940 2,754,968 Vegter et a1. July 17, 1956 2,886,287 Croley May 12, 1959 OTHER REFERENCES 846,987 Germany Aug. 18, 1952 

1. APPARATUS FOR SEPARATING SOLIDS FROM WATER IN A MINE COMPRISING IN COMBINATION, A SLUSHER TRENCH BELOW THE MINE FLOOR; A SUMP BELOW THE MINE FLOOR; A DRAINAGE DITCH IN THE MINE FLOOR DRAINING INTO SAID SUMP; A LIQUIDSOLIDS CYCLONE SEPARATOR HAVING A FEED INLET IN AN UPPER SECTION, A HEAVIER SOLIDS-LIQUID OUTLET IN ITS BOTTOM, AND A LIGHTER SOLIDS-LIQUID OUTLET IN ITS TOP; A RETURN CONDUIT FROM SAID LIGHTER SOLIDS-LIQUID OUTLET TO SAID SUMP; A FIRST FLOATCONTROLLED VALVE IN SAID RETURN CONDUIT HAVING A FLOAT AT A SELECTED LEVEL IN SAID SUMP ADAPTED TO CLOSE SAID FIRST VALVE AS SAID FLOAT RISES; A PUMP HAVING ITS INLET IN A LOWER LEVEL OF SAID SUMP AND ITS OUTLET CONNECTED BY CONDUIT WITH THE FEED INLET OF SAID CYCLONE SEPARATOR; A SCREW TYPE INCLINED CLASSIFIER POSITIONED WITH ITS LOWER END BELOW THE OUTLET OF SAID CYCLONE SEPARATOR AND WITH ITS UPPER END OVER SAID SLUSHER TRENCH FOR DELIVERY OF SOLIDS THERETO; A DISPOSAL LINE CONNECTED WITH SAID LIGHTER SOLIDS-LIQUID OUTLET; A SECOND FLOAT-CONTROLLED VALVE IN SAID DISPOSAL LINE HAVING A SECOND FLOAT AT A SELECTED LEVEL IN SAID SUMP ADAPTED TO CLOSE SAID SECOND VALVE AS SAID SECOND FLOAT LOWERS, SAID FIRST AND SECOND FLOAT-CONTROLLED VALVES BEING ARRANGED SUCH THAT ONE OF SAID VALVES IS AT LEAST PARTIALLY OPEN AT ALL TIMES DURING OPERATION OF SAID PUMP; MEANS FOR CONVEYING THE HEAVIER SOLIDS-LIQUID MATERIAL FROM SAID CYCLONE SEPARATOR TO THE LOWER END OF SAID CLASSIFIER; MEANS FOR CONVEYING OVERFLOW LIQUID FROM THE LOWER END OF SAID CLASSIFIER TO SAID SUMP; AND MEANS FOR OPERATING THE SCREW OF SAID CLASSIFIER. 